(中國科學(xué)院 金屬研究所高溫合金部， 沈陽 110016)
摘 要: 研究了定向凝固N(yùn)iAl合金NiAl-25Cr、 NiAl-15Cr、 NiAl-27Fe-3Nb和NiAl-5Mo-0.5Hf的超塑性行為及其變形機(jī)制。 結(jié)果表明： 合金在一定的變形條件下均表現(xiàn)出超塑性行為，位錯的滑移和攀移行為提供了主要的應(yīng)變量； 超塑性變形過程中的穩(wěn)態(tài)流變源于變形過程中所發(fā)生動態(tài)回復(fù)或再結(jié)晶產(chǎn)生的軟化與應(yīng)變硬化的平衡； 動態(tài)回復(fù)或再結(jié)晶過程一方面在晶粒內(nèi)部削弱了位錯滑動的阻力，另一方面協(xié)調(diào)了晶界之間的變形， 使合金以超塑性方式變形。
關(guān)鍵字: 定向凝固； NiAl合金；超塑性
directionally solidified NiAl alloys
（Superalloy Department, Institute of Metal Research,
Chinese Academy of Sciences, Shenyang 110016, China）
Abstract: The superplastic deformation behavior and mechanism of directionally solidified NiAl alloys(NiAl-25Cr, NiAl-15Cr, NiAl-27Fe-3Nb, NiAl-5Mo-0.5Hf) were investigated. The results reveal that all these alloys exhibit superplastic deformation behavior in certain conditions. Dislocation behavior(glide and climb) provides the main superplastic strain for these alloys. The steady state during superplastic deformation arises from the balance between strain hardening(dislocation behavior) and strain softening(dynamic recovery or recrystallization). Both weakening internal stress and accommodating boundaries from dynamic recovery or recrystallization process make it possible for superplastic deformation to proceed on these alloys.
Key words: directional solidification; NiAl alloys; superplasticity
